The UNEP Addis Ababa Office was established in July 2001. It is an outpost of the Regional Office for Africa, charged with representing UNEP at the Headquarters of the African Union (AU) and the United Nations Economic Commission for Africa (UNECA). It also serves as a UNEP country office for Ethiopia. The primary function of the Addis Ababa Liaison Office as a liaison to the AU is to represent UNEP at meetings and consultations by the AU Commission (Secretariat) and its eight departments (Commissions) each run by a Commissioner. The office also facilitates programmatic collaboration and partnership with the AU.

The Addis Ababa Office is the focal point for UNEP participation in inter-agency collaboration centered in the Addis Ababa duty station. A major part of this is through clusters of UN organizations coordinated by UNECA, which were established for inter-agency support to the New Partnership for Africa's Development (NEPAD). In addition, the Addis office is responsible for bilateral relations with UNECA, which currently hosts the office. In its capacity as a UNEP office for Ethiopia, the Addis Ababa Liaison Office is a member of the UN Country Team coordinated by the United Nation Development Programme (UNDP). The UNEP Addis Ababa Office also works closely with other environmental organizations in Addis Ababa.